Step movement mechanism for typewriters and the like



w. c. ROE 2,089,666

STEP MOVEMENT MECKHANISM FOR TYPEWRITERS AND THE LIKE Aug. 10, 1937.

3 sheets-sheet 1 Original Filed Feb. 5, 1952 gas INVENTOR.

ATTORNEY.

Aug. 10, 1937. w. c. ROE 2,089,655

STEP MOVEMENT MECHANISM FOR TYPEWRITERVS AND THE LIKE Original FiledFeb. 5, 1932 5 Sheets--Sheeil 2 INVENTOR.

M'/mm. C. oe.

BY 5W@ @M ATTORNEY.

W. C. ROE

Aug. 10, 1937.

STEP MOVEMENT MECHANISM FOR TYPEWRITERS AND THE LIKE Original Filed Feb.5, 1932 INVENTOR, h/i//zam C P06.

ATTORNEY.

Patented Aug. 10, 1937 vUNITED STATES PATENT OFFICE STEP MOVEMENTMECHANISM FOR TYPE- WRITERS AND THE LIKE William C. Roe, Elyria,

Ohio, assignor, by

mesne assignments, to Printel Communication Systems, Inc., New York, N.Y., a corporation of New York 13 Claims.

selective current impulses; this class of apparatus being sometimesreferred to as telegraphic typewriters.

The invention relates more particularly to elec- H, trically controlledmechanisms of the step movement class for effecting a step by steppositioning movement of the type cylinder or other corresponding elementof the receiver.

This application is divisional from my appli- 1:, cation Serial No.591,224 led February 5, 1932,

patented Feb. 19, 1935, No..1,991,416, for improvements in Receivers forthe electrical transmission of intelligence. In that application isillustrated and described a complete receiver of the class abovereferred to and an velectrical system for controlling the same andreference may be had thereto for a complete description of parts of thesystem and apparatus herein more briefly described or referred to.

It is an object of the present invention to provide an improvedapparatus of the kind referred to in which transmitted electricalimpulses may actuate a letter printing `type selective apparatuswhereby, in an improved manner, to translate the impulses into lettersand words.

Another object is to provide in a receiver of the class comprising atype cylinder or the like having a plurality of characters thereon andadapted to be selectively moved to position it selectively 35 withrespect to the characters thereon, an improved positioning mechanismtherefor responsive to a variety of predetermined electrical impulsestransmitted thereto.

Another object is to provide in a receiver of 40 the class referred to,having a type cylinder or the like movable rotatively and axially' toposition it selectively with respect to the characters thereon, animproved positioning mechanism therefor.

45 Another object is to provide an improved stepmovement mechanism.

Another object is to provide an improved stepmovement mechanismresponsive to electrical impulses.

a Another object is to provide a step-movement mechanism for selectivelypositioning the type cylinder or the like of a telegraph typewriter orthe like in response to the reception of electrical impulses or groupsof impulses and in which, to

5,-, position the type cylinder, it may be moved rotatively or axiallyand in these directions separately or concurrently.

Other objects will be apparent to those skilled in the art to which myinvention appertains.

My invention is fully disclosed in the following description taken inconnection with the accompanying drawings, in which:

Fig. 1 is a view in some respects diagrammatic illustrating a part of anembodiment of my invention, whereby a type cylinder which I may employmay be selectively moved to printing position and returned to a normalposition;

Fig. 2 is a fragmentary view taken from the plane 2 of Fig. 1;

Fig. 3 is a view taken from plane 3 of Fig. 2;

Fig. 4 is a view to an enlarged scale of a ratchet element which I mayemploy and illustrated in Fig. 1;

Fig. 5 is an elevational view with parts broken away for clearness, ofan apparatus in which my invention may be embodied, and illustratingalso in actual structural form, certain parts which. are illustrateddiagrammatically in Fig. l;

Fig. 6 is a fragmentary view taken from the plane 6 of Fig. 5;

Fig. 'l is a top plan view of an actual embodiment of my invention, withparts broken away to simplify the drawings;

Fig. 8 is a fragmentary view taken from plane 8 of Fig. 'l and withparts omitted for simplicity;

Fig. 9 is a fragmentary view taken from plane 9 of Fig. 5, with theparts drawn to a smaller scale, approximately half of the scale of Fig.5;

Fig. l0 is a fragmentary view taken from plane I0 of Fig. 5.

In general, the apparatus in which my invention is embodied comprises atype cylinder l, mounted for rotary movement on its axis and also formovement longitudinally of its rotary axis. The cylinder hasacylindrical surface thereof divided up into preferably 42 divisions ineach of which may be provided a type character, number or letter. Byrotating the cylinder and/or moving it longitudinally, any one of thecharacters may be brought into position to be printed upon a strip ofpaper as will be more fully described or referred to hereinafter.

The mechanism to be fully described hereinafter for rotating andreciprocating the cylinder I, is actuated by electrical impulsestransmitted to the apparatus from the remote or sending station.Preferably, the impulses are transmitted over two circuits, the impulseson one circuit functioning to rotate the type cylinder l, and those ofthe other functioning to move it longitudinally; and in either case, theapparatus responds to each single impulse to rotate the cylinder asingle space or division or to move it longitudinally a single space ordivision.

In Fig. 1 I have illustrated in semi-diagrammatic form an apparatusembodying the general principles of my invention, and in the otheriigures have illustrated the same mechanism but more as it actuallyappears in a preferred form when produce'd for practical or commercialpurposes.

Referring to Fig. 1, I have reproduced at 1 and 8 two impulse receivingmagnets, each having associated therewith an armature 35 and 38pivotally supported at 31-31 one end of each being adapted to beattracted by the magnet and the other end of each having a finger 38-38engaging an arm 38-38 of a pair of bell cranks "-48, pivoted at 4i-4|.The other arms 42-42 of the similar bell cranks 48-48, are bifurcated attheir free ends to provide ngers,43-44, provided each at the free endsthereof with downwardly projecting pawls 45 and 48. These pawls straddleelongated longitudinally movable ratchet pieces 41-41 provided on theirlateral edges with longitudinally extending rows of teeth 85 and l:respectively, engageable by the pawls 45 and 4 Extending downwardly fromthe ratchet pieces 41-41 are pins 81-81 engaged upon their rearwardsides `by the upper free ends of springs 88-88, see Figs. 5 and 10. Thesprings 88 are preferably formed from nat steel strips supported anddisposed to exert a forward resilient thrust on the pins 81, thrustportions 88-88 being provided on the upper free ends of the springs 88and interposed between the springs and the pins 81, whereby, in allrelative operative positions of the pins 81 and springs 88, the thrustof the spring may be transmitted from the upper extreme end of thespring.

'I'he lower ends of the springs 88 are rigidly connected as by screws 1lto a head 1| rotatably supported in ball bearings 12. but adapted, in amanner to be described, to take up a normal position such as thatillustrated in Fig. 5, in which the springs 88 are bent to continuouslyexert a forward thrust on the pins 81 and the ratchet pieces 41.

In connection with the apparatus thus far described, when a magnet suchas the magnet 1 is energized with one or more impulses, the armature 35thereof will be rocked clockwise and correspondingly rock the bell crank4I counterclockwise against the clockwise torque o1' a spring 15. Thespring 18 normally maintains the pawl 4l against the teeth 85, and thepawl 48 out of engagement with the teeth 88, and the pieces 41 arecontinuously resiliently pruned forward by the springs 88 as abovedescribed. Therefore, upon energization of the magnet 1, say, by oneimpulse, the pawl 48 will be moved into engagement with a tooth 88 totransfer the ratchet piece holding function from the pawl 4l to pawl 48.

When the magnet 1 is de-energized at the end of the said impulse, thespring 15 returns the pawl 48 toward the teeth 85, but the rearwardlyinclined edge, such as the edge 18, of the tooth 88, permits a slightforward movement of the ratchet piece 41 during the inward movement ofthe pawl 48 and outward movement of the pawl 48 so that during thereturn of the pawl 45 toward a small distance by the spring 88 so thatthe pawl 45ss it returns, engages the next sucend oi.' the link 48ceeding tooth 85 and the ratchet piece 41 will thus be advanced adistance corresponding to one tooth space. Thus also, upon energizingthe magnet 1 with a succession of impulses, the bell crank 4l will bevibrated back and forth, in one direction by the magnet i and in theother by the spring 15, and the ratchet piece 41 will be steppedforwardly rapidly a corresponding number of teeth or steps.

In the forward ends of the ratchet pieces 41 are provided upstandingpins 48 over which are looped links 48 and 58 having elongated slots 18and 19 respectively therein. At the outer free is pivoted as at 5| thearm 52 of a bell crank 53 pivotally mounted at 54. A spring 55constantly exerts a counter-clockwise torque on the bell crank 53. Theother arm 63 of the bell crank has a head or pin portion disposed in theannular groove 8i of a shifting head 82 formed integrally with orconnected to the type cylinder i, axially movable upon a supportingshaft 83 but splined or otherwise connected therewith to rotate with theshaft 83. The shaft 88 is supported in adjustable rotational bearings 84and 85.

As will now be apparent, when the upper ratchet piece 41, as viewed inFig. i, is stepped forwardly as above described, the pin 48 will advancein the slot 18 o1' the link 48 or tend to advance therein due to theexceedingly rapid forward movement of the pin 48 and due also to thestepped or intermittent character of its movement. At the same time, thespring 55 will rock the bell crank 53 counter-clockwise and move thetype cylinder i along the shaft 83, the

extent of the movement being determined by the extent of movementvof thepin 48 which in turn is determined by the number of teeth or steps ofadvancement of the ratchet piece 41.

By means of the link and pin connections, 48-48, the intermittentmovement of the ratchet piece 41 may go on freely unhampered by theinertia of the type cylinder and the parts connecting it with theratchet teeth, and these latter parts may move with a steady orcontinuous movement, effected by an independent source of power, namelythe spring 55. At the end of movement of the ratchet piece 41, whereatthe end of the slot 18 engages the pin 48, the type cylinder i isaccurately brought to rest at a position corresponding to the movementof the ratchet piece 41, which, in accordance with the selective numberof impulses, positions the cylinder longitudinally with respect to acharacter thereon.

At the outer end of the link 58, a rack bar 55 is connected, and mountedto move longitudinally in unison with the link 58. A connecting rod 51is pivotally connected to the rack bar 55 at 56 at one end and at theother end is pivoted as at 58 to a crank arm 59 pivotally supported at80. A spring 8| continually exerts resilient torque clockwise on the arm59 and thus, acting through the connecting rod 51, exerts a longitudinalresilient thrust toward the left as viewed in Fig. 5, on the rack bar55'. The rack bar 55 has rack teeth 81 on the under side thereof meshedwith the teeth of a gear 88 secured to the shaft 83 in any suitablemanner and rotatable therewith.

As will now appear, when the ratchet piece 41, the lower one as viewedin Fig. 1, is projected for- Wardly with the intermittent rapid movementabove described, the pin 48 thereof will advance in the slot 18.Concurrently therewith, the link 58 and rack bar 55'- will be pulledforwardly with a steady or continuous movement by the spring 5|,

thereby rotating the gear 88 and the shaft 83 'and the type cylinder I;`and the extent of rthe rotational movement of the type cylinder I willbe determined by the extent of movement of the 5 l ratchet piece 41 andpin 48, the movement being finally stopped, after the ratchet piece 41stops moving, by engagement of the end of the slot 19 with the pin 48;and the rapid intermittent movement of the ratchet piece 41 will not beinterfered with by the relatively great inertia of the other partsmentioned, associated therewith, but the rotary movement of the typecylinder I will be accurately determined and will rotate the typecylinder I, one or more divisions thereof as described hereinbefore.

Since it is desired for 4each impulse In the magnets 1 and 8 torespectively rotate the type cylinder by an amount equal to one divisionthereof and to move it longitudinally an amount equal to one division,the pitch diameter of the gear 88 must be proportioned so that it willturn the type cylinder I one division for each tooth or each stepmovement of the corresponding ratchet piece 41;

and the ratio of the length of the bell crank arms 52 and 63 must beproportioned so that the longitudinal movement given to the typecylinder I will be correct for one complete division thereof for eachtooth space or step of movement of the ratchet piece 41.

1" Where, as illustrated in Fig. 1, the longitudinal movement of thetype cylinder I is in a direction at right angles to the longitudinalmovement of the ratchet pieces 41, the bell crank arms 52 and B3 arepreferably disposed at substantially 37 a right angle to each other andthe pivot point 54 is preferably disposed so that the total movement ofthe bell crank arm will be substantially equal amounts on the oppositesides of corresponding center lines; for example, the bell crank arm 4063 may move from one extreme position to the other, equal amounts onopposite sides of a horizontal line through the pivot 54, and the bellcrank arm 53 correspondingly will move substantially equal amounts onopposite sides of vertical center line through the said pivot.

. By this provision, equal steps on the ratchet pieces 41 will effectequal steps on the type cylinder I. At the same time, the bell crank arm63 may be longer than the bell crank arm 52 whereby any desiredmagnification of movement of the type cylinder I may be effected incorrespondence to any suitable distance between the steps of the ratchetpieces 41. Again, if it be desired to move the type cylinder unequalamounts as, for example, where some of the characters may occupy morelongitudinal length on the cylinder, correspondingly the teeth spaces onthe ratchet pieces 41 may be variable. Furthermore, although the leverarm 52 moves around a supporting pivot 54 and therefore its angularmovement for two steps adjacent the left-hand end of the ratchet piece41 is greater than for successive teeth, nevertheless, by thearrangement of the lever arms above described, this is exactlycompensated for in the movement of the type cylinder I; and for equallyspaced teeth on the ratchet piece 41y the steps taken by the typecylinder I will be equal.

Referring again to Fig. 4, which illustrates one of the ratchet pieces41 to an enlarged scale, I have shown the preferred form of the teeth 65and 66. The teeth 65 comprise each a pawlengaging portion 65 disposedsubstantially at a right angle to the direction of movement of theratchet piece 41 and a rearwardly inwardly inclined portion disposed atan angle of approximately 45 with the portion 65'. The teeth 66comprises each a pawl-engaging portion 66', rearwardly outwardlyinclined at an angle of approximately 30 from the direction of movementand a rearwardly inwardly inclined portion 66", at an angle ofapproximately 45, the shape of the teeth 85 and 68 thus provided beingclearly illustrated in Fig. 4. I find that teeth of these formscooperate more effectively and positively in conjunction with the pawls45 and 46 respectively than other shapes, but as will be understood bythose skilled in the art, the teeth 65 and 66 may be, in form,considerably varied from that illustrated in Fig. 4 without detractingunduly from a. positive accurate ratcheting function thereof.

The type cylinder I may be mounted on the shaft 83 to rotate and moveaxially thereon by various mechanical arrangements, but I prefer theconstruction illustrated in Figs. 1, 2 and 3. As illustrated in thesefigures, the type cylinder has longitudinal grooves between thelongitudinally disposed series of character supporting portions. In oneof these grooves is disposed a key 82' preferably in the form of aslender rod, an end of which is mounted slidably in a bore 8| in thehead 82, and is secured at one end in a suitable recess in a flange 83'of the gear 88. The key 82' is thus rigidly connected to the gear 88,rotates with it and formsl a key or feather for guiding the longitudinalmovements of the type cylinder I, and also serves as a means to rotatethe type cylinder I to communicate thereto rotary or oscillatorymovement of the gear 88.

By this construction, the key or feather 82' may be disposed at arelatively great radial distance from the shaft 83 to reduce to anegligible amount any tendency of the cylinder I to jam thereupon; andthe type cylinder I may be relatively loosely mounted upon the shaft 83and have a relatively loose engagement with the key 82 whereby the typecylinder may in every case move freely and with great rapidity to itsselected position.

At I0 is an electro-magnet having an armature 89 pivotally supported at90 and provided on its free end with an anti-friction wheel or roller 92engaging an inclined portion 93 of a switch indicated generally at 94.The armature 89 is maintained in its counter-clockwise position againstthe tension of a spring 89 by the engagement therewith of one arm 9| ofa bell crank 98 pivotally supported at 99. The other arm |00 of the bellcrank carries, pivoted at its free end as at |04, an equalizing bar |05bridging and engaging the pins 48.

The electric system and circuits by which the elements of the receiverherein described are operated, constitute no part of the presentinvention, that part of the invention being more fully described andillustrated in the above mentioned patent application, Serial No.591,224. It will suffice here to say that upon energization of themagnets 1 and 8 by impulses, these impulses energize the magnet I0 andattract the armature 89, freeing it from the end of the bell crank arm9|. When, as above described, the pins 48--48, either or both of them,move forwardly, they will leave their engagement with the equalizing bar|05 and the bell crank 98 will be free to be rotated clockwise aroundits pivot 99, as, for example, by a tension spring |06, to a positionsuch as that in broken lines at When impulses cease, the energization ofthe magnet Cil I8 ceases (as described in said application) and thespring 88' will retract the armature 88. Movement of the armature 88will be stopped on the end of the arm 8|.

when the bell crank is rotated counter-clockwise upon the restoring ofthe ratchet piece 41 in a manner to be described, the end of the arm 9|will engage and slide over a cam surface Iiii, im the armature 8! movingit counter-clockwise, and will hold it in this position by engagementwith armature 88 on the relatively elevated portion |82.

As more fully described in said patent application, clockwise movementof the armature 89 will close the switch 84 and counter-clockwisemovement will open it. The switch 84 controls energization and operationof a printing magnet indicated generally at I8, see Figs. 1 and. 5disposed under the type wheel I and, in connection with an inking ribbon|84 and a paper strip |25, prints each selected character of the typewheel I upon the paper strip, the ribbon |84 and strip |28 being fedforwardly after each character is printed.

The operation of the printing magnet i2 also operates a switch showngenerally at 21 which controls the energization of a restoring magnetI4, as described in said pending application.

The function of the restoring magnet I4 is to restore the partsmechanically and electrically to their original or normal conditionafter the printing of a character and in preparation for the printing ofthe next successive character. This will now be described.

It will be observed that at the time of energizing the magnet, I4,thertype cylinder I is in some one oi its selective positions andtherefore, the ratchet pieces 41-41 are in one or another of theirforwardly stepped positions.

A depending armature |88, Fig. 5, is pivotally mounted as at |88 toswing toward and from the magnet I4, a pole piece |48 being provided onthe armature |38 upon which the ilux of the magnet I4 may act. The lowerend of the armature |88 is pivotally connected to the two legs I4I-I4Iof a U-shaped link |42, a pin |48 extending through the legs of the linkand through the armature |38. A slot |44 in the legs |4I permitslongitudinal movement of the ends of the pin |43 therein and a spring|45 is placed between the lower end of the armature |88 and the closedend of the link |42, whereby movement of the amature |88 may beinitiated in quick response to the energization of the magnet I4 andwithout waiting for the inertia of the associated parts to be overcome.and movement of the armature transmitted to the link by the armature |88may be cushioned to avoid shock and, for purposes of absorbing inertiaof parts connected to the link |42, to permit the full stroke of thearmature |88 to precede the movement of the said moved parts.

The legs I4I of the link |42 are pivotally connected as at |46 to thelower end of a lever |41 pivotally supported intermediate its ends andadjacent the pivot |46 on a ball bearing support 12. The opposite end ofthe lever |41 more remote from the bearing 12 is, as shown in Figs. 5and 10, provided with a transverse bar 48 normally disposed forwardly ofthe pins 61 which depend from the ratchet pieces 41. And the lever |41is also provided with a laterally extending pin |49 between the bar |48and the bearing 12.

Upon attraction of the armature |38 by the :,osaece magnet I4 in theclockwise direction as viewed in Fig. 5, movement is transmitted throughthe link |42 to the lever |41, rocking it clocklf/ise around the bearing12, causing the bar |48 o move to the right and engage the pins 81 inwhatever forward position they may have been electively disposed, and tomove them back to their normal position, during which movement thel pins48 and the links 49 and 50 operate through the bell crank 58 and throughthe rack bar 55 to restore the printing cylinder to its normal position.The springs 58 and 8| continuously act tending to move the links 48 and88 forwardly and thus, acting through the pins 48, exert forward thruston the ratchet pieces 41-41, but upon the cornpletion of the rearwardmovement of the ratchet pieces 41, by means of the lever |41 asdescribed, the ratchet pawls 45-48 will retain the ratchet pieces 41 intheir rearmost or normal position.

The rearward movement of the pins 48 acts upon the equalizing bar IIIIto rock the bell crank 88 counter-clockwise causing the end of the arm8| thereof to move over the cam |8| against the tension of the spring|88, into a position to engage the portion |02 of the armature 88 inwhich position it may be subsequently held by a shoulder |82' on thearmature. Thus the switch 84 is opened and held opened.

As will presently be referred to again, the magnet |4 will bede-energized after the lever |41 has moved through its stroke to resetthe ratchet pieces 41, and to retract the lever |41 to a positionsuitable for its next operation, a spring |41' is provided connected atone end to the lever |41 and at its opposite end to a suitable point nthe stationary frame of the apparatus, the spring functioning to exert acounter-clockwise torque on the lever |41. When the ratchet pieces 41have been restored to their reset position and held there by the pawlsas above described, the springs 88 are under tension and by their ownreaction upon the head 1| tend to rotate the lever I 41 clockwise inopposition to the tendency of'the spring |41'. When the ratchet pieces41 are ratcheted ahead, the tension in the springs I8 is graduallyreleased, enabling the spring |41 to over-power the springs 88 andretract the lever |41. By suitably proportioning the tension of thesprings 68 and |41', so that they suitably counter-balance each other,the retractive effort of the springs |41' will only be able to retractthe bar |48 a relatively short distance from the pins 61, and as thepins advance with the ratchet pieces 41, the bar |48 will retreat aheadof them so that the bar |48 is at all times a relatively constant andrelatively small distance away from the pins. Therefore, at eachenergization of the magnet I4 and resetting movement of the bar |48, thebar |48 moves only a short distance to engage the pin 61 whether theratchet pieces have been moved ahead one notch or one tooth, or thecomplete range of teeth; and therefore, the bar v |48 engages the pinswith the minimum of impact. The lever I 41 thus has a floating movementwhich maintains the bar |48 in readiness to eil'ect a resetting actionin the minimum of time after energization ofjthe magnet I4, as well aswith the minimum of shock.

At the completion of the operation of the restoring magnet |4 as abovedescribed, its own energizing circuit may be broken by the switch 84 orby the system of circuit and contacts and connections shown anddescribed in said pending application and thereupon all the parts of theapparatus which have not heretofore been reset now move to their normalor reset positions and the entire apparatus is ready for anothercharacter printing cycle of movements.

It is to be observed that by sending impulses to both magnets 1 and 8simultaneously, the type cylinder will rotate and move longitudinally,both movements occurring concurrently and thus the type cylinder ismoved to its selective position with a screwing movement on all or apart of its selection movement.

By reference to Figs. 5, '1, 8, and 10, which illustrate an actualapparatus in which my invention may be embodied, and which apparatus hasbeen developed into somewhat diagrammatic form in Fig. 1, it will beseen that the apparatus may conveniently be assembled upon a framecomprising a base portion 300, a floor portion 30| spaced verticallythereabove and a vertical wall portion 303 standing on or arising froman intermediate portion of the floor 30|.

As shown in Fig. '7 and partly in Fig. 5, the mechanism for selectivelymoving the type cylinder I may conveniently be mounted upon the floorportion 30|; and as shown in Fig. 5, the magnets I3, I4 and 'I and 8 mayconveniently be disposed between the floor portion 30| and the base 300,the magnet |3 and its frame being conveniently suspended from the underside of the floor portion 30|, as may also the magnet |4 and its frame,and magnets 1 and 0, see also Fig. 7, may conveniently be disposed onthe upper side of the base 300.

The magnet as indicated in Fig. '7 may be disposed at right angle to thefloor portion 30| and may be disposed generally thereunder. To avoidcomplications of the drawings, this magnet has been illustrated in ahorizontal position in Fig. 1, but it is believed that the constructionthereof and of the correlated parts will be clear from Fig. 'l withoutfurther illustration or description.

In Fig. 5 a single magnet I4 is illustrated. In some instances I mayemploy two magnets, in which case the second magnet would be discloseddirectly behind the magnet |4 illustrated in Fig. 5. In such case alsoit would be preferred to provide two magnetic circuits one for eachmagnet. As described hereinbefore the magnet circuit of theelectro-magnet I4 comprises a horizontal element 3|| by which it may besupported on the oor portion 30|, a depending leg 3|2 and magnet coreand magnet armature |40; and these parts are preferably duplicatedexcept as' to the armature |40 when two windings are employed.

Such a two magnet construction is shown in Fig. 9 which may beconsidered as viewed from the plane 9 of Fig. 5, with the parts brokenaway at the pivotal bearing |39. The two magnet windings I4a|4a have acommon yoke 320 and the armature |40 may be attracted by both magnetwindings I4a|4a. The armature |40 has a central head portion 32| thereontransversely through which extends a short pin 322, the ends of the pinmounting the inner race elements 323--323 of ball bearings, the outerrace elements of which 324-324 are supported in suitable bores in arms325-325 of the common yoke 320.

The pin 322 corresponds to the pivot bearing element |39 in Fig. 5. Bythis construction the armature |40 may pivot around the ball bearingsdescribed and furthermore, which is an important feature of thisconstruction, the magnetism from the magnets |4a|4a flows not onlythrough the armature |40 and yoke 320 but on its way from one to theother ows into the head 32| and sends through the inner and outerbearing elements 323 and 324 and through the balls such as 326therebetween.

'Ihe magnetism by attracting the balls and their race elements int'otight engagement with each other, eliminate every trace of lost motionin these bearings, and at the same time, due to the ball type ofbearing. does not introduce friction thereby; and furthermore, by thisconstruction, a continuous magnetic path of low reluctance is provided,the only air gap being that between the cores of the magnets |4a,-|4aand the armature |40. Thus, a very efficient as well as silent and lostmotion proof magnetic circuit and armature mounting is provided havingproperties particularly suitable and advantageous in mechanisms of thekind under consideration.

The actual construction of the armature 35 of the magnets 1 and 8 is tobe particularly noted. In the preferred construction, the armaturecomprises a portion 3|5 disposed oppos-ite the core of the magnet, whichportion is pivotally supported at 31, and a relatively slender rodportion 35 rising vertically therefrom, the upper end of which asplainly shown in Figs. 5 and l engages the arm 39 of the bell crank-formratchet pawl supporting pieces. By supporting the magnet 1 on the base300 and the ratcheting mechanism referred to upon the spaced oor 30|, aconsiderable length of rod portion 35 may be provided which makes itpossible to so proportion the length and diameter of the rod portions 35that they may bend under the force applied thereto by the windings 1 and8. Thus for a considerable movement of the upper ends of these rodportions 35 it is only necessary to move the armature portion 3|5 a veryslight distance and. the armature portion 3|5 may respond immediately tothe impulses, followed by movement of the rod portion, the rod portionfunctioning as a resilient rectilinear bar spring. It will be observedthat this movement of the rod portion 35 is distinctly different fromthat of an armature portion which merely moves under the influence ofmagnetism and is retracted by a spring, and in which the inertia of theparts must be continuously overcome, during their vibration, by thedirect pull of the magnet.

The rod-like portions 35 have a natural frequency or period of vibrationwhich may be made to correspond to the rate at which the impulses occur,and thus the effect of the magnetic impulses from the magnets 1 and 8may be described as that of keeping the rod-like armatures in vibrationrather than of bodily moving them.

The armatures 35 may be retracted in any suitable manner but I prefer toretract them by springs 3|63|6, Fig. 7, acting through the bell crankarms 39-39.

Having thus described my invention, I am aware that numerous andextensive departures may be made from the embodiment herein i1-lustrated and described, but without departing from the spirit of myinvention.

I claim:

1. In a step-movement escapement selective mechanism for electricallyactuated typewriters or the like, a ratchet piece comprising a bodyportion having parallel rows of teeth on opposite sides thereof, adouble pawl having a tooth normally in engagement with the teeth of therst row and a pawl'normally laterally spaced from the teeth of thesecond row, means for constraining the 'ratchet piece to move forwardlongitudinally. means for transversely reciprocating the pawl teeth. theteeth of the first row provided with a surface at right angles to thedirection of movement and a surface at an angle of approximately 45 tothe direction of movement, and the teeth of the second row provided withtwo faces at angles of approximately 45 to the direction of movement.

In a step movement escapement selective mechanism for electricallyactuated typewriters or the like, a ratchet piece-comprising a bodyportion having a predetermined direction of movement, and provided withtwo rows of teeth, a 15 double pawl having a tooth engageable with theteeth of one row and a pawl engageable with the teeth of the other row,means for reciprocating the pawl teeth. the teeth of the first rowprovided with a surface at right angles to the direction of movementportion and a surface at an angle of approximately 45 to the directionof movement, and the teeth of the second row provided with two faces atangles of approximately 45 to the direction of movement.

3. In a step movement escapement selective mechanism for electricallyactuated typewriters or the like, a ratchet piece comprising a bodyportion having two rows of teeth thereon, means for constraining thebody portion to move forwardly in generally the direction of the teethrows, a double pawl having two teeth alternately movable into the pathof the rows of teeth upon reciprocation thereof, means for reciprocatingthe pawl teeth, the teeth of one row having each a surface extendingfrom the body portion at an angle sufficiently near 90 with the path ofmovement of the teeth that when engaging one pawl toothin its path, itwill stop movement of the body portion, and the teeth oi' the other rowhav- 40 ing each a surface extending from the body portion at an anglesufficiently less than 90 with the path of movement that upon engagingthe other pawl tooth in its path the tooth will tend to move said pawltooth out of said engagement 45 and out of the path of movement of theratchet teeth.

4.\In a step movement escapement selective mechanismfor electricallyactuated typewriters or the like, a ratchet piece comprising a body 50portion having two rows of teeth thereon, means for constraining thebody portion to move forward in generally the direction of the teethrows,

a double pawl having two teeth alternately movable into the path of therows of teeth upon 55 reciprocation thereof, mea'ns for reciprocatingthe pawl teeth, means for constraining the body portion to move forwardin generally the direction of the teeth rows, the teeth of one rowhaving each a surface extending from the body portion 60 at an angle tothe path of tooth movement sufficiently near 90 that when engaging onepawl tooth in its path, itvwili stop movement oi' the body portion, andthe teeth of the other row having each a surface extending from the bodyportion at an angle sufficiently less than 90 to the path of movementthat upon engaging the other pawl tooth the said teeth of the row willtend to move said pawl tooth out of said engagement 70 and out of thepath of movement, and the teeth of both said rows having other surfacesextending from the body portion at an angle suficiently less than 90that upon movement of the body portion in the reverse direction, thesaid teeth of 75 the body portion tend to move an engaged `pawl ing itto move in the tooth out of engagement and out of the path of movement.

5. In a step movement mechanism an element having a row of ratchetteeth, resilient means constraining it to move in the direction of thetooth row, a pawl and means to oscillate it to engage and disengagesuccessive teeth of the row to permit a step bystep movement of theelement in said direction, means for restoring the element by movementin reverse direction comprising an abutment on the element, anoscillatory arm connected to the resilient means and engageable with theabutment in one direction of oscillation to move the elements and in theother direction of oscillation disengaging the abutment and tensioningthe said resilient means and means to oscillate the arm.

6. In a step movement mechanism an element having a pair of parallelrows of ratchet teeth, resilient means constraining the element to movein the direction of the tooth rows, a pawl and means to oscillate it toengage and disengage the successive teeth of the two rows alternately,tov permit a step by step movement of the element in said direction,means for restoring the element by movement in the reverse directioncomprising an abutment on the element, an oscillatory arm connected tothe resilient means and engageable with the abutment in one direction ofoscillation,

and in the other direction of oscillation disen-` gaging the abutmentand tensioning the said resilient means and means to oscillate the arm.

7. In a step movement mechanism an element having a row oi.' ratchetteeth. means constraindirection of the tooth row, a pawl and means tooscillate it to engage and disengage successive teeth to permit a stepby step movement of the element in said direction, a mechanismcontrolled by movement of the element comprising a member having atelescopic connection with the step mechanism element and independentlyconstrained to move relative thereto.

8. In a step movement mechanism an element having a pair of parallelrows of ratchet teeth, means constraining the element to move in thedirection of the tooth rows, a pawl and means to oscillate it to engageand disengage the successive teeth of the two rows alternately to permita step by step movement of the element in said direction, a mechanismcontrolled by movement of the element comprising a member having atelescopic connection with the said element and independentlyconstrained to move relative thereto.

9. In a step movement mechanism a pair of elements having each a row ofratchet teeth, means constantly and independently constraining theelements to move in the direction of the tooth rows, a pawl associatedwith each element and means to oscillate it to engage and disengage thesuccessive teeth of the element to permit a step by step movement of theelement in said direction, an abutment on each element, a bridgingelement, means yieldably maintaining the bridging element in bridgingengagement with both abutments, and a mechanism connected to thebridging element operable by movement thereof communicated thereto bymovement of either or both step movement elements.

10. In a step mechanism a pair of elements each having a pair ofparallel rows of ratchet teeth, means constraining each elementindependently of the other to move in the direction of the tooth rows, apawl associated with each element 30 ing the element to move in andmeans to oscillate it to engage and disengage the successive teeth. ofthe two rows alternately of the associated element to permit a. step bystep movement of each element in the said direction independently of thestep movement of the other element, an abutment on each element, abridg" ing element, means yieldably maintaining the bridging element inbridging engagement with said abutments, and a mechanism connected tothe bridging element operable by movement thereof, communicated theretoby movement of either or both oi said step movement elements.

1l. l'n a step movement mechanism for typewriters and the like, a pairof elements having each a` row of ratchet teeth, means constantly andindependently constraining the elements to move in the direction o thetooth rows, a pawl associated with each element and means to oscillateit to engage and disengage the successive teeth of the element to permita step by step movement of the element in said direction, amulti-character cylinder movable selectively to printing positions byrotary and axial movements thereof, separate means ior moving thecylinder axially and rotatively, and means connecting said toothedelements respectively to said cylinder moving means.

l2. n a step movement mechanism, an element having a row of ratchetteeth, means constrainthe direction of the tooth row, an oscillatorybell-crank-form pawl, means to oscillate it by one arm thereof, the pawlhaving a portion of the other arm engageable and disengageable withsuccessive teeth upon oscillation thereof and normally constrained inthe direction to engage the teeth, and upon oscillation permitting astep by step movement of the element in the direction `of the tooth rowand the means to oscillate the bell-crank being a resilient reed-likeextension of an electro-magnetic vibratory armature overlapping the saidbell-crank arm at an angle thereto. l

13. ln a step movement mechanism, an element having a pair of parallelrows of ratchet teeth, means. constraining the element to move in thedirection of the tooth rows, an oscillatory bellcrank-form pawl, meansto oscillate it by one arm, the pawl having a portion on the other armengageable and disengageable with successive teeth of the two rowsalternately upon oscillation thereof and normally constrained in thedirection to engage the teeth oi one row, and upon oscillationpermitting a step by step movement of the element in the direction ofthe tooth rows, the means to oscillate the bell-crank being a resilientreed-like extension of an electromagnetic vibratory armature overlappingthe said bell-crank arm at an angle thereto.

WILLIAM C. ROE.

